Vinyl fluoride (i.e., CH.sub.2 .dbd.CHF or VF) is a useful monomer for the preparation of fluorocarbon polymers which have excellent weathering and chemical resistance properties.
Vinyl fluoride can be produced from acetylene and hydrogen fluoride using mercury catalysts. It can also be produced by the dehydrofluorination of 1,1-difluoroethane (i.e., CHF.sub.2 CH.sub.3 or HFC-152a). U.S. Pat. No. 2,892,000 discloses a process for the manufacture of vinyl fluoride and 1,1-difluoroethane. In this process HF and acetylene are passed over a chromium catalyst (e.g., a chromium oxide or chromium salt catalyst) to obtain mixtures of VF and HFC-152a. A process is also disclosed in this patent for the conversion of product HFC-152a to VF using these catalysts. The patent describes using for this conversion of HFC-152a, catalysts which have been used for the reaction of HF and acetylene and whose activity has been reduced; and have then been treated by passing air or oxygen over the heated catalyst (e.g., at about 600 to 700.degree. C. for 1 to 3 hours) whereby it is activated for use in the dehydrofluorination of the HFC-152a to VF (e.g., at temperatures of from about 200.degree. C. to 400.degree. C. and at a rate of about 20 to about 80 volumes per volume of catalyst per hour). There is an ongoing interest in developing more efficient catalysts for the conversion of HFC-152a to VF.